Shorebird Nesting Season Marred By Predators
The shorebird nesting season at Gulf Islands National Seashore is reaching its halfway point. But, protecting the birds and preserving their nests is an uphill battle.
Shorebird nesting at the seashore typically begins in March, when snowy plovers begin arriving from South America. According to National Park Service biologist Mark Nicholas, complicating the situation is the fact that the birds are very small and make their nests in the sand.
Nicholas described the nests saying they are “very simple nests sometimes lined with some seashells, some coquina shells but right on the ground, very inconspicuous as far as the average visitor noticing them. You could actually walk by them very easily.”
The snowy plover continues to nest through mid-July, including a 23-day incubation period and a month or so for the chicks to fledge. However, Nicholas has concluded that the chance of actually achieving that nest success is pretty low these days.
“The shorebirds are definitely having a rough time over the last couple of years. A recent predator that moved into the area, say within the 10 years, is the coyote,” he said.
There are other predators such as blue herons, gull-billed terns and fish crows. But, the coyote has been the most destructive in raiding the nests or eating chicks after they hatch.
Road traffic is another problem. In just one year, recently, the park service documented 155 shorebirds killed on local roadways.
“Both Fort Pickens Road and Highway 399, that cuts from Pensacola to Navarre, we do have a lot of road-kill issues,” said Nicholas. “These are adults flying across the road (that) are struck by vehicles or the chicks are walking across the road or are actually sitting on the road and are struck by vehicles.”
As a result, the Park Service reduces the speed limit on those roadways to 20 miles an hour, giving drivers more time to react and the birds more time to get out of the way.
Given that many of the species that nest Gulf Islands have been listed as threatened or endangered, Nicholas says protection measures are critical.
“Pretty much the national seashores and state parks and undeveloped areas are the only areas where these species reproduce. So, we spend a lot of effort going out to try to post signs to keep the public away, for a number of reasons.
For example, if the birds are disturbed by humans they’re likely to temporarily abandon their nests; which leaves the eggs exposed to predators and direct sunlight. The adult birds actually sit on the eggs to keep them cold, to keep them from cooking from the heat of the sun.
That’s why signs are posted throughout the seashore pointing out where areas are closed.
Nicholas says sign vandalism has been a problem, and there are those who persist in cutting through or hunting shells. But overall he notes that most visitors heed the signs and stay out of the nesting areas.
In either case, a close eye is kept on the shorebirds. Park service biologists and researchers from the State University of New York College of Environmental Science and Forestry are out working on nest location and monitoring.
“The researchers from SUNY, which is Maureen Durkin and her three bio-techs, are banding a lot of the adults, as well as the chicks. So, once we have the bands on the birds, we’re able to follow those family groups with quite a bit of certainty (because they’re banded) and able to determine (you know) when chicks are lost.”
Specifically, Durkin’s research has focused on the impacts of anthropogenic disturbance on Snowy Plovers in the western Florida Panhandle. From 2011-2012, she monitored marked Snowy Plovers at six study sites in the region, in part, to determine reproductive success.
The results of that research by Durkin were chronicled in a Final Report to the Edna Baily Sussman Foundation.
So, there are ongoing efforts to learn more about the habitat and behavior the shorebirds and seabirds, which migrate to the area every year.
The nesting season for the snowy plovers will wrap up in mid-July. Other species will nest through August.